Color screen film and process for manufacturing the same



May l2, 1931. R RUTH I 1,805,009

COLOR SCREEN FILM AND PROCESS FOR IVI/*.NUFACIURING` THE SAME Filed Nov. 8, 1926 7, Carr/'er Patented May 12, 1931 PATENT ori-Ica RUDCIJF RUTH, F SCHWEDT, GERMANY COLOR SCREN FILM AND PROCESS FOR MANUFACTURING SAME Application filed November 8, 1926, Serial No.

It is known to manufacture screen elements for the purposesV of color photography, for instance by atomizing colored solutions in which a more lor less quickly Volatilized liquid is used as the solvent, and

a colloid'as the remaining solid body.

Glass screens are further known in which the support and the screen elements areconstituted by glass. In such a case a rigid screen is formed.

On the contrary, this invention relates to screens with a flexible support, that is to say to color screenilms, and consists in the screen elements and their flexible support being constituted by colloids with identical mechanical and optical properties, for instance by one and the same colloid. In any case, the supports and the screen elements should be soluble in one and the samesolvent. The following results will be obtained thereby:

- 1. An exceedin ly thorough, insoluble connection between t e iexible support and the screen elements is produced.

2. Any deviation in the travel of rays between thesupport and the screen element is avoided, as both have the same coeflicient ofI refraction; the picture will therefore remain unai'ected in thel event of the plane of sep- Y aration between the film and the screen layer being deformed by the process of securing the screen elements to the iilm.

3. No new difficulties are experienced in putting on the layer sensitive to light. On the contrary, it has been found even that the said layer adheres to the screen layer without employing the hitherto usual'adhesive. The solvents hitherto used for nitro-cellulose or acetyl-cellulose, can be used, such as acetone,

glacial acetic acid, ether-alcohol mixtures 40 singly or in mixtures' with each other.

Fig. 1 is a diagrammatical view of a form of apparatus for carrying out the process; Fig. 2 is a cross section jof a film with the flattened powder grain;

Fig. 3 a view\similarto Fig. 2 of the modified process in which the powder grains are first applied to the web; l

Fig. 4 shows the transfer of the powder v grain from the web to the carrier; and

` Fig. 5 shows a cross section of the film with 147,117, and in Germany November 23,1925.

the spherical grain before passing between pressure rollers.

The manufacture Iof the new color screen. film can be effected either by putting on the screen elements directly on the exible colloid support, or by preparing them first on a web of paper or metal and then transferring them to the flexible colloid support, for instance by the transfer process. This latter process has the advantage that the screemelements can be easily ironed or smoothed or levelled at the top and at the bottom.

In the appended'drawings I have shown diagrammatically in Fig. 1, a form of apparatus which may be used to carry out my proc-v 6L essand in Figure 2 I have shown an enlar ed cross-section, a part of a color screen m made in accordance with my process.

Referring to Figure 1, b is a roller or spool carrying film a to be treated. aZ and d are guide rollers, the latter being immersed in liquid contained inv receptacle e. A guide roller Z2 guides the film out of the receptacle e androllers Z and Z pull the 'film past 4the powder receptacle f containing powder which issues from the receptacle f through the screen or sieve g. The film, after receiving a coating of powder, consisting of spherical-shape grains mf, Fig. 5, passes the roller h and brush z', the latter brushing off excess powder. 80 The suction pipe 7c removes any grains which do not adhere to the Jlm and', after passing rollers Z and Z, the former being heated, is wound up on c.

The liquid contained in receptacle e is one 95 which has the property of softening the film supericially, such liquids being known. The screen powder is mixed in the correct color ratio and is applied immediately after the film is softened. The rollers Z and Z place the coated screen under pressure so as to flatten as at n the previously spherical grains and the heated roller Z softens the grains to some extent so as to facilitate flattening.

Ex erience has shown that with this process o working, the grains though slightly iattened as regards their shape, cover the osupport without any gas and without overlapping each other. T e film thus covered with a screen, is wound up at the end of the 10 v machine, in order subsequently to be coated with a layer sensitive to light, and then cut up.

Figure 2 shows the film in cross-section, m

' 5 being the carrier and n the flattened powder grains while n in Fig. 5 shows the spherical grain previous to flattening.

Fig. 3 shows a paper or metal web o to whic the screen film n is first applied as described with regard to Figures 1 and 2 and flattened thereon. Subsequently, according to the transfer process the screen lm 'n is attached to the support m and the paper or metal `web o removed, as shown in Fig. 4

of the drawing. v

Fig. 5 shows the condition of the film before it passes between the rollers Z and Z', and Fig. 2 shows the attened condition of thev grain after the lm'has passed between said rollers.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed I declare what I claim is 1. A process for the manufacture of a color screen film consisting of a supporting colloid and colloidal screen elements the ori ginal spherical shape of which is flattened whereln the supporting colloid is provided 3 with a layer of screen grains and the whole then passed between pressure rollers, of which the roller acting on'the screen grains is heated.

2. A rocess for the manufacture of a color screenlm comprising a colloid support and colloid screen elements, said elements consisting of grain with attened surfaces; the steps of the process consisting in first'applying spherical colloid grain to a web, then at- 40 tening the grains on the web and lastly transferring the flattened grain to the colloid suport. y

p 3. A process for the manufacture of englless color screen films whose scren elements consist of a colloid and are applied directly to the film consisting of a colloid of the same mechanical and optical pro erties as the screen elements, preferably rom the same colloid and are compressed y applying pressure and heat, said lcolloid support provided with the screen elements in a single` layer bein passed between two pressure rollers, of whic the roller acting on the screen grains is heated. s e

In testimony whereof I ax my signature.

. RUDOLF RUTH. 

